If run 'npm dist' after install (without any modifications) and open 'dist/index.html' in the browser then you'll see that there's no image - http://joxi.ru/82Q4jwes1KXldm . Looks like first '/' isn't necessary. Not a big deal, just looks like a small bug.
Anyway, great work! This generator open new possibilities for me to learn new tools in convenient way.